A secondary battery having high application easiness according to a product group and an electric characteristic, such as high energy density, is universally applied in an electric vehicle (EV) and a hybrid vehicle (HV) driven by an electric driving source, or an energy storage system (ESS) or an uninterruptible power supply (UPS) system using a medium and large battery used for a household or an industry, as well as a portable device.
The secondary battery attracts attention as a new energy source for improving environmentally-friendly and energy efficiency in that it is possible to innovatively decrease use of fossil energy, which is the primary advantage, while not generating a by-product when using energy.
A battery applied to the EV or an energy storage source is generally used in a form in which a plurality of unit secondary battery cells is gathered to increase suitability to a high capacity environment, which is, however, not essentially applied to the case where the secondary battery is implemented as a battery of a portable terminal and the like.
In the case where the secondary battery is used in the form in which the plurality of unit secondary battery cells is gathered, when an operation problem, such as a flow of an overcurrent, is generated, there may be a problem in that the unit cell is inflated and damaged by overheating, so that it must be considered that overcharge or overdischarge always needs to be prevented from being applied to the unit cell by measuring and monitoring various state values, such as a voltage and a temperature, of each individual cell.
A battery protecting system in the related art supplies power of a battery to a load by using an integrated circuit (IC), such as a low drop output (LDO) regulator and a DC-DC converter, in which a power supply function and a battery protecting function are embedded, and protects the load from an overvoltage and an overcurrent generated in the battery. However, the IC including the battery protecting function has a problem in momentarily cutting an output when a state problem of the battery is detected, and continuously repeating abnormal on/off of the output when a situation of the load is not changed. Referring to FIGS. 1A and 1B, when a battery performing a normal operation has a problem as illustrated in FIG. 1A, a battery protecting system needs to block power supplied from a battery as denoted with t1. However, the battery protecting system in the related art momentarily cuts an output when an overcurrent and an overvoltage are generated, and continuously repeats abnormal on/off of the output when a situation of a load is not changed as illustrated in FIG. 1B. As described above, when the abnormal on/off is repeated, the battery protecting system and other constituent elements included in a battery management system and a load may perform abnormal operations, and the load fails to be completely protected, thereby causing damage to the load.